Tool for bending press

ABSTRACT

A tool for a bending press is described, the tool comprising a safety element to prevent the tool from accidentally falling from a pressing table of the press.

The invention concerns a tool for a bending press. The tool comprises a safety device to prevent the tool from accidentally falling off the press receiving table, and the safety device has a tool release position from the table and a tool clamping position on the table. The invention also refers to an assembly consisting of the tool and a support to move it to/from a pressing table of the press. The invention also concerns a press equipped with the assembly.

Such a tool is known, for example, from U.S. Pat. No. 6,467,327, which describes a safety element that protrudes from the tool surface and is engageable in a recess of the press table. The safety element prevents the tool from falling, but by manually pressing a button the safety element is retracted and the tool can be pulled out of the table, basically in a direction perpendicular to the horizontal length of the table.

To use such a tool, an operator is needed who manually operates the safety device. Or, to increase productivity, the tool change is automated with a programmed mechanical manipulator, which however must also be equipped with a special gripper that not only grips and holds the tool, but also handles the safety device.

Grippers that mechanically operate the safety device are already well known but have as a disadvantage the scarce flexibility in managing different types of tools. For example, these grippers are only able to operate tools in which the button is placed in a known position.

Whether with a manual operator or a robot, the additional problem remains that the button is located only on one side of the tool. Since very often the tool has to be turned by 180° on the table to allow bending, the rotation operation is always very slow, and sometimes impossible for a robot.

The main object of the invention is to provide a tool to improve the state of the art, in particular that allows a better flexibility and speed of replacement of the same.

An aspect of the invention concerns a tool for a bending press, the tool comprising

two opposite faces that have a bending edge of the tool as a common border,

a safety element to prevent the tool from accidentally falling off a bending table of the press,

the safety element being movable between a tool release position from the table and a tool clamping position on the table, wherein

the tool also comprises a control element that

is able to control the safety element to move it between said positions, and

is mounted on the tool so as to be accessible from both said opposite faces.

Since the control element is reachable from any of the opposite faces, one can move the safety element by acting on the control element from any of the opposite faces, and thus unhook/hook the tool. As a result, the rotation of the tool on the table and/or the removal of the tool is greatly simplified.

Another aspect of the invention concerns a system or assembly comprising the tool and a tool support adapted to move it to and from a pressing table of the press. The system or assembly shares all of the variants listed below for the tool and the support. Another aspect of the invention concerns a press comprising the tool, a vertically movable pressing table on which the tool can be mounted, and a tool support adapted to move it to and from the table. The press shares all of the variants listed below for the tool and the support.

In a preferred variant, the tool comprises

a pass-through cavity that passes through both the opposite faces,

the control element being placed inside the cavity and being configured for

detecting the presence of a tool support when present inside the cavity, and

move the safety element between the two positions as a function of the presence detected by the control element.

Thanks to the aforementioned cavity, the control element is accessible to the support from each of the opposite faces. Therefore, the support can be inserted in said cavity coming from any of the opposite faces to unhook/hook the tool, and the rotation of the tool on the table and/or its removal is very simplified.

The interchangeable tool is more advantageous for a bending press, but also tools for other machines can also be configured according to the invention.

In most cases, the common border comprises a tool bending tip.

The safety element may have many embodiments. The simplest one envisages a pin or a protruding tooth that is retractable inside the contour or body of the tool, in particular inside the contour of one of said opposite faces.

The safety element may move through

-   -   a linear translation, e.g. along an axis orthogonal to a plane         that contains one of the two opposite faces or to a plane that         is parallel to one of the two opposite faces, and/or     -   a rotation, e.g. about an axis contained in one of the two         opposite faces or parallel to one of the two opposite faces.

The pass-through cavity is preferably only one, and/or a through-opening or a through-hole, e.g. of circular or polygonal cross-section.

To simplify the tool, preferably the control element is a mechanical sensor, such as for example a movable slider or a cam to convert the presence and/or a thrust of the support when it is inside the pass-through cavity into a movement to be transmitted to the safety element by means of a mechanism, in particular a mechanism for moving the safety element between the two positions as a function of the presence of the control element inside the cavity. For example, the mechanical sensor may be a spherical or circular element, e.g. mounted rolling or rotatable, to facilitate the sliding contact with said support.

In particular, the mechanical sensor is mounted inside the tool, e.g. inside said pass-through cavity and/or inside an internal cavity of the tool, so as to be protruding from a wall of the through-cavity, and so as to be able to be pushed by said support and transmit movement to the safety element.

More specifically, the mechanical sensor is mounted inside the tool so as to be linearly translatable along an axis parallel to one or each of the opposite faces, and/or along an axis contained between said opposite faces.

The mechanical sensor is preferably mounted on a movable slide comprising an inclined plane (e.g. a slot or a cam) that engages a portion of the safety element (e.g. a pin), so that a linear displacement of the inclined plane causes a linear displacement of the safety element from one of said positions to the other.

Or the movable slide may comprise a cam portion that engages a portion of the safety element, so that a displacement of the cam portion causes a linear displacement of the safety element from one of said positions to the other.

In particular, the linear displacement of the inclined plane lies on a plane orthogonal to that in which the linear displacement of the safety element lies.

In particular, the support comprises a head or end that can be inserted into the through-cavity.

Preferably the head or end of the support that can be inserted into the pass-through cavity comprises an inclined plane that is

tilted with respect to the axis of the (support's) advance inside the cavity, and

located so as to meet the mechanical sensor and slide it on the inclined plane so as to displace it along an axis lying in a plane orthogonal to the advance axis inside the cavity.

Preferably the support head that can be inserted into the pass-through cavity comprises a blocking element that is

mounted in a cavity that opens on the outer surface of the head of the support,

movable, along an axis lying in a plane orthogonal to the axis of advance inside the cavity, between two positions:

a retracted position wherein it does not protrude from the outer surface of the support head, and

an extracted position wherein it protrudes from the outer surface of the support head.

The blocking element can then come out of the support head and press against the walls of the pass-through cavity of the tool for greater stability.

More preferably, for even greater stability, the walls of the pass-through cavity of the tool comprise a recess complementary to the blocking element for receiving a free end of the blocking element. When the blocking element enters the complementary recess, the head of the support and the tool become rigidly integral with each other and a strong constraint is formed that counteracts their detachment.

The movement of the blocking element can be controlled in various ways, e.g. by a pneumatic or electromagnetic linear actuator or an electric motor.

Preferably, the movement of the blocking element is controlled by a control element that is linearly translatable with respect to the support head.

E.g. the control element and the blocking element are coupled to each other by means of an inclined plane or a cam coupling. This way a translation of the control element is converted into a translation of the blocking element, i.e. a linear back-and-forth movement of the control element along the advance direction of the support is converted into a linear back-and-forth movement of the blocking element within a plane orthogonal to the axis of advance inside the cavity, between said two positions.

In a preferred variant, the control element is a rod mounted linearly sliding inside the support.

Preferably, the head or end of the support that can be inserted into the pass- through cavity has a cross section, considered in a plane orthogonal to the advance direction of the support inside the tool cavity, which is different from a circumference, so that the tool cavity and the head or end of the support form an irrotational prismatic pair. For example, this cross-section is polygonal, elliptical or lobed.

The tool preferably comprises an elastic element, e.g. a spring, for pushing the safety element toward the tool blocking position.

In particular, the elastic element is mounted inside an internal cavity of the tool.

The tool preferably comprises a single pass-through cavity into which a support head can be inserted. To improve stability, the cross-section of the pass-through cavity and that of the support head form an anti-rotational prismatic closure-shape pair, i.e. the support inserted in the pass-through cavity can only move by linear relative motion and without rotation with respect to the tool, with the constraint that the inner surface of the pass-through cavity constantly slides during the relative motion on the external surface of the support head. For example, the pass-through cavity has a polygonal or oval cross-section, and the support head has a cross-section complementary to the cross-section of the pass-through cavity.

Further characteristics and advantages of the invention will result more from the description of a particular embodiment, illustrated in the attached drawings. in which:

FIG. 1 shows an exploded view of the tool and a support;

FIGS. 2 and 3 show a side view in vertical median cross-section of the tool coupled to a support in two different configurations;

FIGS. 4 and 5 show a top view of the horizontal median cross-section of the tool coupled to a support in two different configurations.

In the figures equal numbers indicate equal parts; and in order not to crowd the figures some references are not repeated.

FIG. 1 shows a tool MC that can be mounted on the table of a bending press (not shown).

The tool MC has two opposite faces or sides 10, 12 which have as a common border a bending tip or edge 14 of the tool. The type of bending tip or edge 14 of the tool is unessential, as are its external dimensions.

The two opposite faces or sides 10, 12 are locally contained in, or parallel to, two imaginary planes Y1, Y2 which are in use vertical, parallel and offset to each other.

Usually in a tool of this type, the two opposite faces or sides 10, 12 have steps and/or undercuts, for necessity of bending or assembly on the press, but altogether the two opposite faces or sides 10, 12 develop along or parallel to or in a neighborhood of the planes Y1, Y2. Therefore, profile deviations from the perfect plain geometry represented by the imaginary planes Y1, Y2 are not relevant for the following description.

With respect to a shank 18 of the tool MC, a safety tooth 20 can protrude from surface 10 to prevent the tool MC from accidentally falling off the table.

The tooth 20 is mounted inside the body of tool MC so that it is movable along an X axis, orthogonal to the planes Y1 and Y2, between a tool release position, wherein it does not protrude from the face 10 and shank 18, and a tool blocking position, wherein it protrudes from the face 10 and the shank 18.

The tool MC comprises a through-hole 30, with an axis parallel to X, which opens on both the opposite faces 10, 12.

Protruding from a side wall of the hole 30 is a wheel 40, hinged on a sliding slide 50 equipped with a plane 52 inclined with respect to the X axis (the inclined plane 52 lies on an imaginary plane that intersects the planes Y1 and Y2 with equal angle).

The slide 50 is translatable inside the body of the tool MC along a axis Y3 parallel to Y1 and Y2 and orthogonal to X.

The inclined plane 52 slides against a portion of the tooth 20, so as to move it along X and make it move inside the surface of the face 10. The opposite movement of the tooth 20, coming out of the surface of the face 10, is ensured by a spring 60 that works in compression along Y3 on the tooth 20 to counteract the thrust of the slide 50.

The wheel 40 acts as a sensor to detect the presence of a tool support 90. The support 90 has a head 92 that is insertable into the hole 30 by means of a linear translation along an axis X2, parallel to X.

When the support 90, e.g. comprising or consisting of a head 92, is inserted into the hole 30 from any of the faces 10 or 12 (FIG. 2), it meets at a certain point the bulk of the wheel 40 and displaces it outside the cross-section of the hole 30 along Y3 (FIG. 3). The slide 50 moves integrally along Y3 together with the wheel 40, and so does the inclined plane 52, which in turn pushes the tooth 20 and causes it to retract inside the face or side 10 overcoming the force of the spring 60. Thus the tool MC is released from the press table.

When the head 92 is pulled out of the hole 30, the force of the spring 60 no longer has any opposition and can push the tooth 20, the slide 50 and the wheel 40 into the starting position, wherein the tooth 20 protrudes from the face 10 and holds the tool MC on the press table.

In order to keep the tool MC vertical when moving, in the tool MC the cross-section of the hole 30 and that of the head 92 are complementary and form an irrotational prismatic pair. In the example, the cross-section of the hole 30 and the head 92 are oval, but may be square, polygonal or star-shaped to create opposition to rotation.

Note that the wheel 40 can be indifferently reached and actuated by a support 90 that approaches the tool MC on the side of the face 10 or the face 12.

In order to facilitate the movement of the wheel 40, the head 92 comprises at its tip a plane 94 inclined with respect to the planes Y1, Y2. Then the inclined plane 94 can meet the wheel 40, which rolls over it while pushing the slide 50 up.

To improve the mutual blocking between the head 92 and the tool MC, the head 92 comprises a moving tooth 200 which by moving can protrude from the outer lateral surface of the head 92 see FIGS. 1, 4 and 5.

The mobile tooth 200 is operable by a rod 96 coaxially mounted inside a cavity of the support 90 so as to translate along X2. The movable tooth 200 and the rod 96 are coupled through a slot 98 in the rod 96 and a pin 210. The slot 98 is tilted with respect to X2 so as to convert a back-and-forth shift of the rod 96 along X2 into a back-and-forth shift of the tooth 200 in a direction orthogonal to X2.

The hole 30 has a recess 33 on its inner walls that is complementary to the tooth 200.

Then, after the head 92 has been inserted into the hole 30 (FIG. 4), the rod 96 is operated to move it, and thus the tooth 200 is moved to make it protrude from the outer lateral surface of the head 92. The tooth 200 enters the recess 33, and makes the head 92 and the tool MC locked together and integral with each other (FIG. 5).

To extract the head from the hole 30 one acts in reversed sequence.

The support 90 and/or the rod 96 are operated e.g. with well-known actuators.

The operating mechanism of the tooth 20 is enclosed within the body of the tool MC, e.g. by a screwed plate 100. 

1. Tool for a bending press, the tool comprising: two opposite faces which have as a common border a bending edge of the tool, a safety element to prevent the tool from accidentally falling from a pressing table of the press, the safety element being movable between a tool release position from the table and a tool locking position on the table, a control element which is able to control the safety element to move it between said positions, and is mounted on the tool so as to be accessible from both said opposite faces, a single pass-through cavity passing through both said opposite faces, the control element being placed inside the cavity and being configured for detecting the presence of a tool support when present inside the cavity, and moving the safety element between the two positions as a function of the presence detected by the control element.
 2. Tool according to claim 1, wherein the safety element comprises a pin or a protruding tooth which can be retracted inside the profile of the tool.
 3. Tool according to claim 1, wherein the control element is a movable slide for converting the presence and/or a thrust of the support when it is inside the pass-through cavity into a displacement to be transmitted to the safety element via a mechanism.
 4. Tool according to claim 1, wherein the sensor is mechanical and mounted inside said pass-through cavity, inside an internal cavity of the tool, so as to protrude from a wall of the pass-through cavity, and so that it can be pushed by said support and transmit motion to the safety element.
 5. Tool according to claim 1, wherein the sensor is mounted inside the tool so as to be linearly translatable along an axis parallel to one or each of said opposite faces, and/or along an axis contained between said opposite faces.
 6. Assembly comprising: a tool according to claim 1, a support that can be inserted into the tool's pass-through cavity to move it, the support comprising an inclined plane that is inclined with respect to the axis of advance of the support inside the cavity, and positioned so as to meet the sensor and slide it on the inclined plane so as to move it along an axis lying in a plane orthogonal to the axis of advance inside the cavity.
 7. The assembly according to claim 6, wherein the support comprises a head which can be inserted into the pass-through cavity, the head comprising a blocking element, for locking the head integrally with the tool, which is mounted in a cavity that opens on the external surface of the head of the support, and movable, along an axis lying in a plane orthogonal to the axis of advancement of the head inside the cavity, between two positions: a retracted position in which it does not protrude from the external surface of the head of the support, and an extracted position in which it protrudes from the external surface of the head of the support.
 8. The assembly according to claim 7, wherein the walls of the pass-through cavity of the tool comprise a recess complementary to the blocking element to receive a free end of the locking element.
 9. The assembly according to claim 7, comprising a control element which is translatable linearly with respect to the head of the support, so that the movement of the blocking element is controlled by the control element, the latter and the locking element being preferably coupled by means of an inclined plane or a cam-coupling to convert a translation of the control element into a translation of the locking element.
 10. The assembly according to claim 9, wherein the control element is a linearly sliding rod mounted inside the support.
 11. Tool according to claim 2, wherein the control element is a movable slide for converting the presence and/or a thrust of the support when it is inside the pass-through cavity into a displacement to be transmitted to the safety element via a mechanism.
 12. Tool according to claim 2, wherein the sensor is mechanical and mounted inside said pass-through cavity, inside an internal cavity of the tool, so as to protrude from a wall of the pass-through cavity, and so that it can be pushed by said support and transmit motion to the safety element.
 13. Tool according to claim 2, wherein the sensor is mounted inside the tool so as to be linearly translatable along an axis parallel to one or each of said opposite faces, and/or along an axis contained between said opposite faces.
 14. Tool according to claim 3, wherein the sensor is mounted inside the tool so as to be linearly translatable along an axis parallel to one or each of said opposite faces, and/or along an axis contained between said opposite faces.
 15. Tool according to claim 1, wherein the sensor is mounted inside the tool so as to be linearly translatable along an axis parallel to one or each of said opposite faces, and/or along an axis contained between said opposite faces.
 16. The assembly according to claim 8, comprising a control element which is translatable linearly with respect to the head of the support, so that the movement of the blocking element is controlled by the control element, the latter and the locking element being preferably coupled by means of an inclined plane or a cam-coupling to convert a translation of the control element into a translation of the locking element.
 17. The assembly according to claim 17, wherein the control element is a linearly sliding rod mounted inside the support. 